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We reported that the dissolved tungsten bronze (H x WO 3) exhibits the best activity for selective C C bond cleavage. The active species with low coordinated and low valent W site calls for the selectivity to C 2 fragments via a homolytic cleavage of C C bond cleavage. [Display omitted] • The formation of a chelated metalacyclic complex with 5-membered ring is critical for C C cleavage of glucose on the W-based catalyst. • The low-valent W center experiences a redox cycle (+V → +VI → +V) during the C C cleavage that accounts for the high reactivity of W-based catalyst. • The surface decoration of reduced and low-coordinated W site could be efficient for selective cellulose conversion in aqueous phase. In chemistry, selective activation of C C bonds enables the direct production of valuable chemicals from widely available and inexpensive natural materials but remains a fundamental challenge due to their kinetic inertness. The selective cleavage of C C bond in glucose by tungsten oxide-based catalysts in aqueous phase pioneers a path for converting cellulose biomass into valuable ethylene glycol. However, debates regarding the active phase and how it selectively breaks the C 6 into C 2 fragments have persisted for over a decade. In this study, we present a comprehensive mechanistic investigation by modeling three potential active phases, i.e. the reduced WO 3-x surface, the dissolved tungstic acid, and tungsten bronze, in explicit solvent waters. By constrained molecular dynamics simulations, we have demonstrated that the low-coordinated W center can chelate with glucose, forming a metallacyclic complex with a 5-membered ring after the protonation of carbonyl group. The formation of 5-membered ring serves as the premise for the selectivity to C 2 fragments via homolytic cleavage of C C bond. Furthermore, the reduced W5+ center is suggested to be crucial in facilitating the cleavage process by stabilizing the dissociated C 4 intermediates via a redox process. In conclusion, we propose that the surface decoration of reduced and low-coordinated W sites can act as active heterogeneous catalysts for the selective conversion of cellulose in aqueous phase. These recent findings have the potential to provide valuable insights and strategies for C C bond activation in both biomass conversion and organic synthesis. [ABSTRACT FROM AUTHOR]